[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132341
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAR 13 2014

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2200 UTC.

...SPECIAL FEATURES...
A COLD FRONT EXTENDS FROM 32N68W THROUGH THE CENTRAL BAHAMAS...
NORTHERN CUBA AND THE YUCATAN CHANNEL TO THE NORTHERN YUCATAN
PENINSULA. GALE FORCE SW WINDS LIE N OF 30N WITHIN 180 NM EAST
OF THE FRONT BUT ARE EXPECTED TO DIMINISH BELOW GALE FORCE BY
0000 UTC. SEE THE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO
HEADERS MIAHSFAT2/ FZNT02 KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 05N08W TO
02N15W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
02N15W TO THE EQUATOR AT 31W. ISOLATED MODERATE CONVECTION IS
SOUTH OF 04N BETWEEN 20W-30W WHILE SCATTERED MODERATE CONVECTION
LIES SOUTH OF 02N BETWEEN 30W-40W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY SHOWS THE VIGOROUS UPPER LEVEL TROUGH THAT
BROUGHT A STRONG COLD FRONT TROUGH THE GULF OF MEXICO HAS PUSHED
EASTWARD ALONG THE U.S. EASTERN SEABOARD. THE COLD FRONT WAS
ANALYZED ACROSS THE YUCATAN CHANNEL TO THE FAR NORTHERN YUCATAN
PENINSULA AT 1800 UTC. THE STRONG WINDS THAT ACCOMPANIED THE
FRONT AREA DIMINISHING. A FRESH TO STRONG NORTH TO NORTHEAST
BREEZE IS CONFINED TO THE AREA EAST OF 93W AND IS EXPECTED TO
DIMINISH BY FRI AFTERNOON AS THE TROUGH AND COLD FRONT PULL
FARTHER AWAY FROM THE AREA. 1027 MB HIGH PRES CENTERED OVER
CENTRAL LOUISIANA IS DRIVING THE SURFACE WINDS...WITH
SOUTHEASTERLY RETURN FLOW NOW FOUND OVER THE NORTHWESTERN GULF.
FARTHER SOUTH...VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW
SHALLOW CLOUDS BANKED AGAINST THE MOUNTAINS SOUTH AND WEST OF
TAMPICO MEXICO. THERE IS NO SIGNIFICANT PRECIPITATION OVER THE
GULF AT THIS TIME. THIS HIGH PRES IS FORECAST TO SLIDE EASTWARD
ALONG 30N/31N THROUGH FRIDAY WITH SOUTHERLY RETURN FLOW
EXPANDING EASTWARD INTO THE CENTRAL GULF INTO THE UPCOMING
WEEKEND.

CARIBBEAN SEA...
THE AFOREMENTIONED COLD FRONT ASSOCIATED WITH THE VIGOROUS UPPER
LEVEL TROUGH TO THE NORTH HAS MADE ITS WAY TO THE YUCATAN
CHANNEL. A PRE-FRONTAL SURFACE TROUGH LIES AHEAD OF IT FROM
CENTRAL CUBA TO THE COAST NEAR THE BORDER OF BELIZE AND MEXICO.
SHOWERS PRIMARILY LIE WITHIN 60 NM EAST OF THE FRONT AS WELL AS
BETWEEN THE FRONT AND TROUGH OVER THE NW CARIBBEAN...WITH
ISOLATED THUNDERSTORMS FOUND OVER CENTRAL CUBA. ISOLATED SHOWERS
AND THUNDERSTORMS ALSO CAN BE FOUND FARTHER SOUTH IN THE
VICINITY OF THE GULF OF HONDURAS. THE TROUGH AND COLD FRONT ARE
EXPECTED TO MERGE OVERNIGHT TONIGHT...WITH THE FRONT STRETCHING
FROM THE WINDWARD PASSAGE THE BELIZE FRI NIGHT AND DISSIPATING
BY SAT NIGHT. OTHERWISE...THE REMAINDER OF THE BASIN IS UNDER
THE INFLUENCE OF A MIDDLE TO UPPER LEVEL RIDGE STEMMING FROM AN
ANTICYCLONE NEAR 13N76W. WATER VAPOR IMAGERY INDICATES VERY DRY
AIR WITH SUBSIDENCE PREVAILING GENERALLY SOUTH OF 18N E OF 80W.
THE ONLY SIGNIFICANT AREAS OF ISOLATED SHOWERS ARE FOUND FROM
WITHIN 120 NM SW OF THE SW TIP OF HAITI AND OVER THE EASTERN
CARIBBEAN WITHIN 90 NM EITHER SIDE OF A LINE FROM 17N69W TO
11N63W. TRADE WINDS ARE RELATIVELY WEAK ACROSS THE CARIBBEAN AS
HIGH PRES TO THE NE IS BEING FORCED AWAY FROM THE AREA BY THE
FRONTAL BOUNDARY MOVING ACROSS THE YUCATAN CHANNEL...DIMINISHING
THE PRES GRADIENT ACROSS THE AREA.

...HISPANIOLA...
VISIBLE SATELLITE IMAGERY SHOWS SCATTERED SHOWERS ARE CLUSTERED
CLOSE TO THE MOUNTAIN RANGES OVER HISPANIOLA...WITH LIGHT WINDS
PREVENTING THEM FROM STRAYING FAR FROM THE AREA OF GREATEST
OROGRAPHIC ENHANCEMENT. ELSEWHERE...MOSTLY CLEAR SKIES AND FAIR
CONDITIONS ARE NOTED. THE FRONTAL BOUNDARY MOVING ACROSS THE SW
NORTH ATLC AND THROUGH THE YUCATAN CHANNEL WILL BEGIN TO IMPACT
HISPANIOLA FRI AS MOISTURE POOLED AHEAD OF THE FRONT INCREASES
THE PROBABILITY OF PRECIPITATION FRI INTO SAT. THE FRONT IS
EXPECTED TO WEAKEN AS IT REACHES THE WINDWARD PASSAGE FRI
EVENING AND DISSIPATE OVER NORTHERN HISPANIOLA BY SAT EVENING.

ATLANTIC OCEAN...
A VIGOROUS UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY
MOVING OFF THE U.S. EASTERN SEABOARD. ITS ASSOCIATED COLD FRONT
AT THE SURFACE EXTENDS FROM 32N68W THROUGH THE CENTRAL BAHAMAS
TO NORTHERN CUBA NEAR 23N80W. GALE FORCE WINDS AHEAD OF THE
FRONT N OF 30N ARE DISCUSSED IN THE SPECIAL FEATURES SECTION
ABOVE. A PRE-FRONTAL SURFACE TROUGH LIES APPROXIMATELY 75 NM
AHEAD OF THE FRONT SOUTH OF 25N. THIS SURFACE TROUGH IS EXPECTED
TO MERGE WITH THE FRONT OVERNIGHT TONIGHT. SCATTERED SHOWERS AND
THUNDERSTORMS CAN BE FOUND WITHIN 120 NM EAST OF THE FRONT NORTH
OF 25N...WITH MORE ISOLATED SHOWERS AND THUNDERSTORMS FOUND
SOUTH OF 25N. FARTHER EAST...THE REMAINDER OF THE CENTRAL AND
EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE STEMMING
FROM A 1028 MB HIGH PRES CENTER NEAR 35N40W. A WEAKENING SURFACE
TROUGH REMAINS EMBEDDED WITHIN THE WESTERN PERIPHERY OF THE
RIDGE. THE TROUGH IS ANALYZED FROM 29N49W SW TO 23N57W. ISOLATED
SHOWERS AND THUNDERSTORMS LIE WITHIN 240 NM E OF THE TROUGH FROM
27N-29N...WITH ISOLATED SHOWERS ALSO FOUND WITHIN 240 NM E OF
THE TROUGH FROM 23N-25N. THIS TROUGH SHOULD WEAKEN AS IT MOVES
WESTWARD TOWARD THE COLD FRONT OVER THE SW NORTH ATLC.
FINALLY...ON THE EASTERN PERIPHERY OF THE RIDGE LIES A COLD
FRONT THAT EXTENDS INTO THE DISCUSSION AREA NEAR 32N30W THEN SW
TO 27N35W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 90 NM
SOUTHEAST OF THE FRONT. THIS FRONT IS EXPECTED TO DISSIPATE OVER
FORECAST WATERS FRI...POSSIBLY LEAVING A TROUGH BEHIND SAT.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
SCHAUER


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